Conventionally, there has been known an electronic commerce website allowing the purchase of transaction objects, such as the purchase of items or the reservation of services. In such a website, there is a web page on which information on transaction objects are posted with respect to each of the transaction objects. Also, such a website provides a function of allowing a user to register arbitrary transaction objects in a reference list. The reference list is, for example, a list holding a reference to information on transaction objects, such as a URL of information on transaction objects. The reference list is referred to as, for example, a bookmark or the like. The user registers, for example, interesting transaction objects, transaction objects as purchase candidates, favorite transaction objects, and the like, in the reference list. This makes it possible to easily access information on the transaction objects from the reference list.
There is a case where the transaction objects registered in the reference list are no longer necessary for the user due to, for example, a change in a user's situation. Therefore, if the user registers the transaction objects in the reference list one after another, unnecessary transaction objects also are included and a large number of transaction objects are registered in the reference list, resulting in the enlargement of the reference list. Thus, there is a case where it is necessary for the user to search a desired transaction object from the reference list and access information on the transaction object. In order to prevent the enlargement of the reference list, the reference list needs to be organized. However, in this case, it is necessary for the user to search unnecessary transaction objects from a large number of transaction objects and delete the unnecessary transaction objects from the reference list. There is a case where it takes time and effort to perform this operation.
In this regard, Patent Literature 1 discloses a technique that collectively deletes URLs a user has not accessed for a predetermined time, among URLs registered in bookmarks.